Carburetor



NOV. 12, 1935. J JACKS 2,020,413

CARBURETOR Filed May 11, 1927 gwuexntoz L/HCDE 17. L/HQKE.

Patented Nov. 12 1935 PATENT OFFICE GARBURETOR Jacob A. Jacks, Detroit,

Mich., assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application May 11, 1927, Serial No. 190,525

14 Claims.

This invention relates to carburetors. Carburetors as ordinarily constructed, wherein fuel is drawn by engine suction from a supply source i. e., a spray nozzle and float chamber, into 5 a mixing chamber and thence into the engine cylinders, may fail to supply a proper mixture under certain operating conditions. For example, when starting the engine, the fuel in the supply passages of the carburetors is at rest and, as is well known, an appreciable force and time are required to set it in motion. The inertia of the fuel itself, as well as the friction between the walls of the passages and the fuel, and other factors, no doubt contribute to this efiect. In addition, when the throttle is suddenly opened for rapidly increasing the engine speed, the fuel in the supply passages must be rapidly accelerated and the factors just .mentioned again operate in a manner tending to prevent introduction of a suflicient supply of fuel to the engine.

An object of the present invention is to supply a fuel mixture suitable for most efficient engine operationunder substantially all operating conditions.

-Another object is to automatically enrich the fuel mixture under certain operating conditions.

A specific object is to increase the supply of fuel to the mixing chamber of a carburetor, when the engine is being started or rapidly accelerated.

An additional object is to control the supply of fuel in a carburetor in accordance with the rate or degree of opening or closing of the throttle.

A further object is to control an auxiliary fuel supply source substantially in accordance with the difference in pressure between separated points in the fuel mixture intake passage.

A feature of the invention is a carburetor including means for injecting an extra supply of fuel into the mixing chamber under certain op:- erating conditions.

Another feature is a carburetor including a pump adapted to be operated by engine suction for augmenting the supply of fuel to the mixing chamber.

Another feature is a carburetor provided with a pump including a flexible walled vessel, actuated by engine suction, having a nozzle projecting into the carburetor spray nozzle, whereby fuel is squirted into the mixing chamber and is prevented from being forced back into the float chamber.

The one figure of the drawing shows a carburetor embodying this invention.

The carburetor shown in the drawing includes a casing I providing a fuel mixture passage or mixing chamber l I having an air intake opening at 12, and an outlet opening at 3, the latter opening being adapted to be connected to the intake manifold of an internal combustion engine for supplying fuel mixture to the cylinders thereof. 5 Within the passage H is a throttle valve I4 and supplementing the opening I2, is an auxiliary air intake opening l5 controlled by an air valve (not shown) having a control spring contained within the cap or casing I6. The carburetor also includes a float chamber IT, a spray nozzle i8 comprising, in the present instance, an elongated tube and a hollow nut but which may be of one piece construction, a Venturi or spray mixing tube 9, an auxiliary fuel pump 20 and a pump conduit 2 l The float chamber H which encloses a fuel level control mechanism of any suitable type adapted to maintain a predetermined level of fuel in the spray nozzle, includes a fuel supply pipe 22 adapted to be connected to a fuel supply tank. A duct 23 and annular passagesZ and 26 in the casing I0 provide communication between the float chamber and the spray nozzle 18 whereby liquid fuel is supplied to the spray nozzle. The upper end of the spray nozzle is positioned at the restricted portion of the spray mixing tube l9, whereby the current of air drawn in from the intake opening [2 through this tube by engine suction causes liquid fuel to be drawn from the nozzle and vaporized to form a combustible mixture with the air. The throttle valve It is adapted to be actuated by an arm 21 for controlling the amount of fuel mixture supplied to the engine cylinders.

The pump includes a casing having a body portion 28 and a flanged cover 29, the latter including a hollow neck 30 threaded into an opening in a depending portion 3! of the carburetor casing ill below the bottom of the spray nozzle. An annular gasket 31 is provided between a shoulder 38 on the neck 30 and the edge of the extension 3| for effecting a liquid tight joint. Inside of the casing 28 is positioned a flexible metal vessel or bellows 32 constructed preferably of resilient material 7 tending to contract. The vessel 32 has its lower end closed and its upper periphery attached to a diaphragm 33 having a central perforation or hole 34 over which an auxiliary spray tube 35 is positioned, whereby the duct in the tube communicates via the perforation with the inside of the vessel 32. If desired, the vessel 32 may be of non-resilient material and a coil spring or other suitable device may be provided to cause a contraction of the Walls of the vessel and to resist expansion thereof in an axial direction. The diaphragm 33 is clamped at its periphery between the cover 29 and the body portion 28 of the casing, an annular gasket 39 being positioned between the cover and the diaphragm for effecting a liquid tight joint. The upper end of the tube 35 is telescoped within the lower end of the nozzle l8 and the outer diameter of the tube is smaller than the inner diameter of the nozzle 18, whereby a relatively small annular passage 2% is provided. The tube 35 preferably extends into the tub-e [8 a distance such that the passage 26 offers appreciable resistance to the sudden back-flow of fuel through this passage and the passage 24, into the passage 23 and the float chamber. In other words, the resistance offered to the back-flow of fuel by the passages 23, 24 and 26 is greater than that offered by the spray nozzle I8, so that fuel squirted from the tube 35 will pass out of the spray nozzle rather than into the float chamber.

This carburetor operates in the following manner: Liquid fuel in the float chamber ll passes through the duct 23 and the passages 25 and 26 into the spray nozzle I8, until the level of the fuel in the spray nozzle is the same as the level in the float chamber. When the throttle is open, the air current through spray mixing tube 59 draws liquid fuel from the spray nozzle l8 causing it to be vaporized and mixed with the air. Assuming that the throttle I4 is closed and that the engine is running, the suction produced by the engine is effective at the opening 36 of the conduit 2i and this suction, transmitted through the conduit to the casing 28, causes the flexible vessel 32 to be extended against its spring action. In this position, the vessel is filled with liquid fuel drawn in through the tube 35. When the throttle I4 is suddenly opened, to accelerate the engine, the suction above the throttle is reduced and accordingly the flexible vessel 32 is caused to contract suddenly and, in so doing, a stream of fuel is squirted from the tube 35 up through the spray nozzle l8 into the mixing tube ill to enrich the mixture at the time when the inertia of the fuel in the spray nozzle, float chamber and connecting passages tends to cause the mixture to be too lean. After the throttle is open and the inertia of the fuel in the spray nozzle has been overcome, the bellows 32 ceases action so that the mixture does not become too rich. If the throttle is opened gradually, the bellows 32 will contract gradually and the amount of fuel forced from the tube 35 into the nozzle [8 is reduced to correspond to the requirements of the engine. Minor changes of the throttle opening will not appreciably affect the mixture, because the fuel supplied directly from the float chamber to the spray nozzle will be adequate and the amount supplied by the bellows will be negligible. During closing of the throttle, the bellows 32 expands and draws in fuel from the nozzle [8 through the tube 35. This results in a beneficial effect in that the supply of fuel. to the mixing chamber is somewhat reduced, thereby rendering the throttle control more sensitive. The reduction in fuel supply by this means however will be slight, because the bellows can only draw in fuel at a low rate, since the passage in the tube 35 is small and since the fuel supplied from the float chamber during this time tends to maintain the the bellows is controlled in accordance with the difference in pressure on opposite sides of the throttle. However, the amount of expansion and contraction of the bellows and the rate at which the movement thereof occurs will be dependent 5 upon the rate of opening and the degree of opening of the throttle.

The amount of fuel supplied by the pump 20 to the mixing chamber is determined in part by the dimensions of the various passages and ducts and 10 these elements are so designed as to supply the desired amount of fuel for most eflicient operation of the engine. In a device actually constructed and found to operate efiiciently, the outer diameter of the end of the tube 35 was 15 inch, the inner diameter of the adjacent portion of the spray nozzle was inch so that the annular passage 26 had a radial width of inch. The annular passage 24 was larger than the passage 25. The casing 28 had an inner diameter of 1% 20 inches and an inside length of 1%; inches.

This invention is of particular advantage in that it enriches the fuel mixture during starting of the engine and during rapid accelerations thereof to such a degree that choking of the 25 engine is prevented and a smooth, efficient and powerful operation of the engine is secured whereby the control of the motor vehicle, in which the engine is included, is materially facilitated.

Although this invention has been described in 30 connection with a specific embodiment, it is to be understood that the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art and that the invention is to be limited only as indi- 3'5 cated by the scope of the appended claims.

What is claimed is:

1. In a carburetor, a fuel mixture supply passage having an outlet opening, a mixing tube and a spray nozzle positioned in said passage, a. 4 throttle valve between said mixing tube and said outlet, a float chamber communicating with said nozzle, and a flexible metal vessel having a tube telescoped within said spray nozzle and a casing for said vessel, said casing being closed except for 45 a duct communicating with said fuel mixture supply passage between said throttle and said outlet opening.

2. In a carburetor, a casing including a mixing chamber, a spray nozzle in said chamber, means 50 for maintaining liquid fuel in said nozzle, and means for overcoming the inertia of said fuel comprising an expansible vessel below and connected to said mixing chamber said vessel having a tube telescoped in said nozzle and adapted to 55 inject fuel through said nozzle.

3. In a carburetor, a casing including a mixing chamber, a float chamber, a spray nozzle, a conduit in said casing connecting said nozzle tosaid float chamber, means including a tube telescoped 60 within said nozzle for injecting liquid fuel into said mixing chamber, said telescoped tube being of such dimensions as to provide a small passage between the nozzle and the tube for retarding back-flow of fuel into the float chamber and per- 6 mitting normal flow of fuel from said float chamber to said nozzle.

4. In a carburetor, in combination, a mixing tube, a spray nozzle in the mixing tube, a spray tube telescoping within the spray nozzle, and a 0 flexible vessel to intermittently discharge fuel into the spray nozzle through said spray tube.

5. In a carburetor, in combination, a throttle valve, a spray nozzle, a spray tube having one end projecting into the spray nozzle and the other end 75 communicating with a flexible member and a conduit for transmitting the pressure above the throttle valve to the flexible member.

6. In a carburetor, in combination, a throttle valve, a spray nozzle, a spray tube having one end projecting into the spray nozzle and the other end communicating with a flexible vessel enclosed in a chamber and a conduit for transmitting the pressure above the throttle valve to the chamber enclosing the flexible vessel.

7. In a carburetor, in combination, a throttle valve, a spray nozzle, a spray tube telescopically arranged with respect to the spray nozzle, a chamber, a flexible vessel in the chamber connecting with the spray tube and a conduit to" transmit the pressure above the throttle valve to the chamber, whereby the flexible vessel will expand when the throttle valve is substantially closed and will contract and discharge fuel into the spray nozzle when the throttle valve is opened quickly.

8. In a carburetor, in combination, a mixing tube, a spray nozzle in the mixing tube and means for supplying an additional quantity of fuel to the spray nozzle comprising a spray tube having one end projecting into the spray nozzle and the other end communicating with a flexible pressure responsive device.

9. In a carburetor, in combination, a throttle valve, a spray nozzle and means for supplying an additional quantity of fuel to the spray nozzle when the throttle valve is quickly opened comprising a spray tube telescopically arranged with respect to the spray nozzle and connected with a bellows pressure responsive device subjected to the pressure above the throttle valve.

10. In a carburetor including an intake manifold, a float chamber and a mixing chamber, means for positively injecting a supplementary fuel charge into said mixing chamber comprising an auxiliary chamber having a flexible bellows disposed therein, and means whereby the auxiliary chamber space outside the bellows is in communication with the intake manifold, and the space inside the bellows is in communication with the float chamber and the mixing chamber.

11. In a carburetor including an intake manifold, a fuel supply chamber and a mixing chamber, means for positively injecting a supplementary fuel charge into said mixing chamber comprising an auxiliary chamber, a diaphragm having an opening therein covering the auxiliary chamber, a depending flexible bellows having its 5 lower end closed and its open upper end attached to the diaphragm over the opening therein, means connecting the auxiliary chamber with the intake manifold, and a nozzle extending into the mixing chamber connected with the opening in the diaphragm.

12. In a carburetor including a mixing chamber, an intake manifold and an auxiliary chamber, as a means of injecting a supplemetary fuel charge into said mixing chamber, a channeled connection leading from the auxiliary chamber to the intake manifold, said carburetor being arranged with a channel between the mixing chamher and the auxiliary chamber, a bellows having one open and one closed end, disposed with the open end across the mouth of the auxiliary chamber whereby the bellows is caused, under normal running conditions, to assume a distended position by reason of the weight of fuel within and above the bellows and is caused to partially 001- lapse, expelling some of the fuel, on rapid opening of the throttle by reason of the increase in pressure in the intake manifold.

13. In a carburetor, in combination, a throttle valve, a mixing chamber, a tube leading into the mixing chamber, an auxiliary chamber, a flexible bellows in the chamber connecting with the tube and a conduit to transmit the pressure above the throttle valve to the auxiliary chamber, whereby the flexible bellows will expand when the throttle valve is substantially closed and will contract and discharge fuel into the mixing chamber when the throttle valve is opened quickly.

14. In a carburetor, a mixing chamber, a spray nozzle in the mixing chamber and a spray tube having an end protruding into the spray nozzle and spaced from the walls thereof, the inner diameter of the tube being of the order of 4 inch and the outside diameter of the spray tube being of the order of inch whereby the resistance to the flow of fuel through the passage is greater than the resistance to flow through the nozzle.

JACOB A. JACKS. 

